Abscisic acid (ABA) is a plant hormone that plays a major role in plant growth, development and response to abiotic stress. ABA causes many of its cellular responses by binding to a soluble family of receptors called PYR/PYL proteins, which contain a ligand-binding pocket for ABA and other agonists. Direct application of ABA to plants has been shown to improve their water use efficiency. However, ABA is difficult and expensive to prepare and itself unstable to environmental conditions and therefor unsuitable for large scale agricultural applications. It is therefore desirable to search for ABA agonists that may be useful for improving plant tolerance to environment stress such as drought, inhibit seed germination, regulate plant growth and improve crop yield.
WO2013/148339 reported a new ABA agonist, quinabactin, which binds to the PYR/PRL receptor proteins and causes an abscisic acid response in vivo. Quinabactin has been shown to induce stomatal closure, suppress of water loss and promote drought tolerance.
There is a need to identify improved agonists of abscisic acid for improving plant growth and development, and plant tolerance to environmental stresses. The present invention relates to novel analogs of quinabactin that have improved properties. Benefits of the compounds of the present invention include enhanced tolerance to abiotic stress, improved inhibition of seed germination, better regulation of crop growth, improved crop yield, and/or improved physical properties resulting in better plant uptake, water solubility, chemical stability or physical stability.